Various embodiments of the present disclosure relate to a nonvolatile memory device, a method of operating the same, and a memory cell array thereof and, more particularly, to a nonvolatile memory device having a single-layer gate, a method of operating the same, and a memory cell array thereof.
Various nonvolatile memory cell and memory cell array structures have been proposed for a memory device in which data stored in the memory cells is retained without access to power. In the conventional memory cell structure of a nonvolatile memory device, a stacked gate structure in which a gate insulating layer, a floating gate, an inter-gate insulating layer, and a control gate are sequentially arranged in a vertical direction has generally been employed. However, as the size of electronic apparatus continues to shrink and fabrication technology is developed, semiconductor devices capable of performing various functions have been embedded in one semiconductor chip. This type of semiconductor chip layout, called a system on chip (SoC), includes logic devices and memory devices and has emerged as a core part of advanced digital products. A fabrication technology of an embedded nonvolatile memory device embedded in a system on chip (SoC) has been developed.
The embedded nonvolatile memory device embedded in the system on chip (SoC) is fabricated in process steps that are the same as those of the logic devices of the system on chip (SoC). The nonvolatile memory device may employ a transistor with a stacked gate structure, while the logic devices employ a transistor with a single gate structure. When the nonvolatile memory device with a stacked gate structure and the logic devices with a single gate structure are embedded in the same substrate, the fabrication process thereof becomes very complicated. Therefore, attempts have been made to employ a single-layer gate in a nonvolatile memory device instead of the stacked gate structure. In employing a nonvolatile memory device having a single-layer gate, the system on chip (SoC) may be easily fabricated through the general fabrication processes of complementary metal oxide semiconductors (CMOS) used when fabricating logic devices.